[PATCH net-next 4/4] bridge: fdb: write to used and updated at most once per jiffy

[Nikolay Aleksandrov]

Writing once per jiffy is enough to limit the bridge's false sharing.
After this change the bridge doesn't show up in the local load HitM stats.

Suggested-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com>
---
 net/bridge/br_fdb.c   | 3 ++-
 net/bridge/br_input.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 5cbed5c0db88..5028691fa68a 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -597,7 +597,8 @@ void br_fdb_update(struct net_bridge *br, struct 
net_bridge_port *source,
                                fdb->dst = source;
                                fdb_modified = true;
                        }
-                       fdb->updated = jiffies;
+                       if (jiffies != fdb->updated)
+                               fdb->updated = jiffies;
                        if (unlikely(added_by_user))
                                fdb->added_by_user = 1;
                        if (unlikely(fdb_modified))
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index fba38d8a1a08..220943f920d2 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -198,7 +198,8 @@ int br_handle_frame_finish(struct net *net, struct sock 
*sk, struct sk_buff *skb
                if (dst->is_local)
                        return br_pass_frame_up(skb);
 
-               dst->used = jiffies;
+               if (jiffies != dst->used)
+                       dst->used = jiffies;
                br_forward(dst->dst, skb, local_rcv, false);
        } else {
                if (!mcast_hit)
-- 
2.1.4